1. Field of the Invention
This invention relates generally to remote control devices and, more particularly, to simple, lowcost infrared control devices particularly useful for triggering the release of a camera shutter.
2. Description of the Prior Art
Various remote control devices suitable for remotely controlling the operation of a camera shutter are known. Such systems have used radio waves, acoustic waves and light beams including infrared light beams to control a shutter release remotely. Examples of radio wave controlled systems are disclosed in U.S. Pat. Nos. 3,148,330; 3,805,281; 3,922,961; 3,961,342; 4,433,903 and 4,801,959, while an example of an acoustically controlled system is disclosed in U.S. Pat. No. 4,290,685. Examples of light controlled systems are disclosed in U.S. Pat. Nos. 4,048,540; 4,091,398; 4,707,127 and 5,014,080. The '540 and '398 patents describe flash attachments that operate at a high output level for flash photography and at a low level to serve as a remote control. The '127 and '080 patents describe remote control shutter release systems that utilize light emitting diodes as a source of light or infrared energy. Infrared control systems are also commonly utilized to control the operation of television receivers, video cassette recorders and associated peripheral equipment.
While all of the above-described systems provide a way to control a shutter release mechanism automatically, radio systems are relatively complex and care must be taken to prevent the radio frequency waves that are generated by such systems from interfering with other electronic devices in the area. Approval of such systems by the Federal Communications Commission may also be required and such approval may be time consuming and costly to obtain. Acoustic systems may be in the supersonic or audible range, with older systems being in the audible range and utilizing tuning forks or bars or the like to generate the control signal mechanically. Later systems generated an ultrasonic signal electronically and utilized a transducer to convert the ultrasonic electrical signal to an acoustic signal. The disadvantages of the aforementioned acoustic systems were complexity, particularly in the mechanical systems, and a tendency for the acoustic transducers to become less efficient with time.
The device disclosed in U.S. Pat. No. 5,014,080 combines a shutter release function with a distance-to-subject determining system, but does not address the problems associated with inadvertently triggering the shutter due to ambient light sources. Another system such as the one described in U.S. Pat. No. 4,707,127 discloses a remote triggering system that is simple and inexpensive, but also does not address the problem of inadvertent triggering of the shutter by extraneous ambient light sources. Optical systems used to control devices such as radio and television receiving and recording systems require a multi-function signalling capability, and are consequently more complex than necessary for remote shutter release applications. Dual function photo flash devices are cumbersome and consume relatively large amounts of power and, consequently, are not well suited for remote control applications.